FreeRTOS里的Tick定时器在哪里配置的

Posted 2021-09-23 快乐的老鼠

int main(void)
{
	nvic_priority_group_set(NVIC_PRIGROUP_PRE4_SUB0);

	xTaskCreate(GUI_Task, "GUI_Task", configMINIMAL_STACK_SIZE * 8, NULL, tskIDLE_PRIORITY + 1, NULL);
	/* start scheduler */
	vTaskStartScheduler();
	while (1) {
	}
}

FreeRTOS10.1版本

从main函数看非常的简洁以至于我都不知道在哪儿开启了Tick定时器

跟踪vTaskStartScheduler() -> vPortSetupTimerInterrupt()

void vPortSetupTimerInterrupt( void )
	{
		/* Calculate the constants required to configure the tick interrupt. */
		#if( configUSE_TICKLESS_IDLE == 1 )
		{
			ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ );
			xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick;
			ulStoppedTimerCompensation = portMISSED_COUNTS_FACTOR / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
		}
		#endif /* configUSE_TICKLESS_IDLE */

		/* Stop and clear the SysTick. */
		portNVIC_SYSTICK_CTRL_REG = 0UL;
		portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;

		/* Configure SysTick to interrupt at the requested rate. */
		portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
		portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );
	}